The realization of optically active structures with direct-write printing has been challenging, particularly in spatially constrained microfluidic devices for point-of-care (POC) sensing and diagnostics. The existing techniques are limited by resolution, accessibility, and multi-step fabrication constraints. There remains a need for new light-based techniques that can create the arbitrary patterns of particles immobilized on the substrates. The systems and methods discussed herein address these and other needs.